Caption: Alexander Graham Bell (1847-1922), British scientist and inventor. Bell was born in Scotland but moved to Boston, USA in 1871, to lecture on teaching the deaf to speak. In 1873 he was appointed professor of vocal physiology at Boston University. His experiments on the transmission of sound by electricity led to his designs for the multiple telegraph machine and the telephone, which were patented in 1875 and 1876 respectively. Bell also investigated the potential uses of sonar and various equipment for the deaf. He was a winner of the John Fritz Medal, awarded by the American Association of Engineering Societies.